Inbred maize line PH22G

ABSTRACT

An inbred maize line, designated PH22G, the plants and seeds of inbred maize line PH22G, methods for producing a maize plant produced by crossing the inbred line PH22G with itself or with another maize plant, and hybrid maize seeds and plants produced by crossing the inbred line PH22G with another maize line or plant.

FIELD OF THE INVENTION

This invention is in the field of maize breeding, specifically relatingto an inbred maize line designated PH22G.

BACKGROUND OF THE INVENTION

The goal of plant breeding is to combine in a single variety or hybridvarious desirable traits. For field crops, these traits may includeresistance to diseases and insects, tolerance to heat and drought,reducing the time to crop maturity, greater yield, and better agronomicquality. With mechanical harvesting of many crops, uniformity of plantcharacteristics such as germination and stand establishment, growthrate, maturity, and plant and ear height, is important.

Field crops are bred through techniques that take advantage of theplant's method of pollination. A plant is self-pollinated if pollen fromone flower is transferred to the same or another flower of the sameplant. A plant is cross-pollinated if the pollen comes from a flower ona different plant.

Plants that have been self-pollinated and selected for type for manygenerations become homozygous at almost all gene loci and produce auniform population of true breeding progeny. A cross between twodifferent homozygous lines produces a uniform population of hybridplants that may be heterozygous for many gene loci. A cross of twoplants each heterozygous at a number of gene loci will produce apopulation of hybrid plants that differ genetically and will not beuniform.

Maize (zea mays L.), often referred to as corn in the United States, canbe bred by both self-pollination and cross-pollination techniques. Maizehas separate male and female flowers on the same plant, located on thetassel and the ear, respectively. Natural pollination occurs in maizewhen wind blows pollen from the tassels to the silks that protrude fromthe tops of the ears.

A reliable method of controlling male fertility in plants offers theopportunity for improved plant breeding. This is especially true fordevelopment of maize hybrids, which relies upon some sort of malesterility system. There are several options for controlling malefertility available to breeders, such as: manual or mechanicalemasculation (or detasseling), cytoplasmic male sterility, genetic malesterility, gametocides and the like.

Hybrid maize seed is typically produced by a male sterility systemincorporating manual or mechanical detasseling. Alternate strips of twoinbreds of maize are planted in a field, and the pollen-bearing tasselsare removed from one of the inbreds (female). Providing that there issufficient isolation from sources of foreign maize pollen, the ears ofthe detasseled inbred will be fertilized only from the other inbred(male), and the resulting seed is therefore hybrid and will form hybridplants.

The laborious, and occasionally unreliable, detasseling process can beavoided by using cytoplasmic male-sterile (CMS) inbreds. Plants of a CMSinbred are male sterile as a result of factors resulting from thecytoplasmic, as opposed to the nuclear, genome. Thus, thischaracteristic is inherited exclusively through the female parent inmaize plants, since only the female provides cytoplasm to the fertilizedseed. CMS plants are fertilized with pollen from another inbred that isnot male-sterile. Pollen from the second inbred may or may notcontribute genes that make the hybrid plants male-fertile. Seed fromdetasseled fertile maize and CMS i produced seed of the same hybrid canbe blended to insure that adequate pollen loads are available forfertilization when the hybrid plants are grown.

There are several methods of conferring genetic male sterilityavailable, such as multiple mutant genes at separate locations withinthe genome that confer male sterility, as disclosed in U.S. Pat. Nos.4,654,465 and 4,727,219 to Brar et al. and chromosomal translocations asdescribed by Patterson in U.S. Pat. Nos. 3,861,709 and 3,710,511. Theseand all patents referred to are incorporated by reference. In additionto these methods, Albertsen et al., of Pioneer Hi-Bred, U.S. patentapplication Ser. No. 07/848,433, have developed a system of nuclear malesterility which includes: identifying a gene which is critical to malefertility; silencing this native gene which is critical to malefertility; removing the native promoter from the essential malefertility gene and replacing it with an inducible promoter; insertingthis genetically engineered gene back into the plant; and thus creatinga plant that is male sterile because the inducible promoter is not "on"resulting in the male fertility gene not being transcribed. Fertility isrestored by inducing, or turning "on", the promoter, which in turnallows the gene that confers male fertility to be transcribed.

There are many other methods of conferring genetic male sterility in theart, each with its own benefits and drawbacks. These methods use avariety of approaches such as delivering into the plant a gene encodinga cytotoxic substance associated with a male tissue specific promoter oran antisense system in which a gene critical to fertility is identifiedand an antisense to that gene is inserted in the plant (see:Fabinjanski, et al. EPO 89/3010153.8 publication no. 329,308 and PCTapplication PCT/CA90/00037 published as WO 90/08828).

Another system useful in controlling male sterility makes use ofgametocides. Gametocides are not a genetic system, but rather a topicalapplication of chemicals. These chemicals affect cells that are criticalto male fertility. The application of these chemicals affects fertilityin the plants only for the growing season in which the gametocide isapplied (see Carlson, Glenn R., U.S. Pat. No. 4,936,904). Application ofthe gametocide, timing of the application and genotype specificity oftenlimit the usefulness of the approach.

The use of male sterile inbreds is but one factor in the production ofmaize hybrids. The development of maize hybrids requires, in general,the development of homozygous inbred lines, the crossing of these lines,and the evaluation of the crosses. Pedigree breeding and recurrentselection breeding methods are used to develop inbred lines frombreeding populations. Breeding programs combine the genetic backgroundsfrom two or more inbred lines or various other germplasm sources intobreeding pools from which new inbred lines are developed by selfing andselection of desired phenotypes. The new inbreds are crossed with otherinbred lines and the hybrids from these crosses are evaluated todetermine which of those have commercial potential. Plant breeding andhybrid development are expensive and time consuming processes.

Pedigree breeding starts with the crossing of two genotypes, each ofwhich may have one or more desirable characteristics that is lacking inthe other or which complements the other. If the two original parents donot provide all the desired characteristics, other sources can beincluded in the breeding population. In the pedigree method, superiorplants are selfed and selected in successive generations. In thesucceeding generations the heterozygous condition gives way tohomogeneous lines as a result of self-pollination and selection.Typically in the pedigree method of breeding five or more generations ofselfing and selection is practiced: F₁ →F₂ ; F₃ →F₄ ; F₄ →F₅, etc.

Recurrent selection breeding, backcrossing for example, can be used toimprove an inbred line. Backcrossing can be used to transfer a specificdesirable trait from one inbred or source to an inbred that lacks thattrait. This can be accomplished, for example, by first crossing asuperior inbred (recurrent parent) to a donor inbred (non-recurrentparent), that carries the appropriate gene(s) for the trait in question.The progeny of this cross is then mated back to the superior recurrentparent followed by selection in the resultant progeny for the desiredtrait to be transferred from the non-recurrent parent. After five ormore backcross generations with selection for the desired trait, theprogeny will be heterozygous for loci controlling the characteristicbeing transferred, but will be like the superior parent for most oralmost all other genes. The last backcross generation is then selfed togive pure breeding progeny for the gene(s) being transferred.

A single cross maize hybrid results from the cross of two inbred lines,each of which has a genotype that complements the genotype of the other.The hybrid progeny of the first generation is designated F₁. In thedevelopment of commercial hybrids only the F₁ hybrid plants are sought.Preferred F₁ hybrids are more vigorous than their inbred parents. Thishybrid vigor, or heterosis, can be manifested in many polygenic traits,including increased vegetative growth and increased yield.

The development of a maize hybrid involves three steps: (1) theselection of plants from various germplasm pools for initial breedingcrosses; (2) the selfing of the selected plants from the breedingcrosses for several generations to produce a series of inbred lines,which, although different from each other, breed true and are highlyuniform; and (3) crossing the selected inbred lines with differentinbred lines to produce the hybrid progeny (F₁). During the inbreedingprocess in maize, the vigor of the lines decreases. Vigor is restoredwhen two different inbred lines are crossed to produce the hybridprogeny (F₁). An important consequence of the homozygosity andhomogeneity of the inbred lines is that the hybrid between a definedpair of inbreds will always be the same. Once the inbreds that give asuperior hybrid have been identified, the hybrid seed can be reproducedindefinitely as long as the homogeneity of the inbred parents ismaintained.

A single cross hybrid is produced when two inbred lines are crossed toproduce the F₁ progeny. A double cross hybrid is produced from fourinbred lines crossed in pairs (A×B and C×D) and then the two F₁ hybridsare crossed again (A×B)×(C×D). Much of the hybrid vigor exhibited by F₁hybrids is lost in the next generation (F₂). Consequently, seed fromhybrids is not used for planting stock.

Hybrid seed production requires elimination or inactivation of pollenproduced by the female parent. Incomplete removal or inactivation of thepollen provides the potential for self pollination. This inadvertentlyself pollinated seed may be unintentionally harvested and packaged withhybrid seed.

Once the seed is planted, it is possible to identify and select theseself pollinated plants. These self pollinated plants will be geneticallyequivalent to the female inbred line used to produce the hybrid.

Typically these self pollinated plants can be identified and selecteddue to their decreased vigor. Female selfs are identified by their lessvigorous appearance for vegetative and/or reproductive characteristics,including shorter plant height, small ear size, ear and kernel shape,cob color, or other characteristics.

Identification of these self pollinated lines can also be accomplishedthrough molecular marker analyses. See, "The Identification of FemaleSelfs in Hybrid Maize: A Comparison Using Electrophoresis andMorphology", Smith, J. S. C. and Wych, R. D., Seed Science andTechnology 14, pp. 1-8 (1995), the disclosure of which is expresslyincorporated herein by reference. Through these technologies, thehomozygosity of the self pollinated line can be verified by analyzingallelic composition at various loci along the genome. Those methodsallow for rapid identification of the invention disclosed herein. Seealso, "Identification of Atypical Plants in Hybrid Maize Seed byPostcontrol and Electrophoresis" Sarca, V. et al., Probleme de GeneticaTeoritica si Aplicata Vol. 20 (1) p. 29-42.

As is readily apparent to one skilled in the art, the foregoing are onlytwo of the various ways by which the inbred can be obtained by thoselooking to use the germplasm. Other means are available, and the aboveexamples are illustrative only.

Maize is an important and valuable field crop. Thus, a continuing goalof plant breeders is to develop high-yielding maize hybrids that areagronomically sound based on stable inbred lines. The reasons for thisgoal are obvious: to maximize the amount of grain produced with theinputs used and minimize susceptibility of the crop to pests andenvironmental stresses. To accomplish this goal, the maize breeder mustselect and develop superior inbred parental lines for producing hybrids.This requires identification and selection of genetically uniqueindividuals that occur in a segregating population. The segregatingpopulation is the result of a combination of crossover events plus theindependent assortment of specific combinations of alleles at many geneloci that results in specific genotypes. The probability of selectingany one individual with a specific genotype from a breeding cross isinfinitesimal due to the large number of segregating genes and theunlimited recombinations of these genes, some of which may be closelylinked. However, the genetic variation among individual progeny of abreeding cross allows for the identification of rare and valuable newgenotypes. These new genotypes are neither predictable nor incrementalin value, but rather the result of manifested genetic variation combinedwith selection methods, environments and the actions of the breeder.

Thus, even if the entire genotypes of the parents of the breeding crosswere characterized and a desired genotype known, only a few, if any,individuals having the desired genotype may be found in a largesegregating F₂ population. Typically, however, neither the genotypes ofthe breeding cross parents nor the desired genotype to be selected isknown in any detail. In addition, it is not known how the desiredgenotype would react with the environment. This genotype by environmentinteraction is an important, yet unpredictable, factor in plantbreeding. A breeder of ordinary skill in the art cannot predict thegenotype, how that genotype will interact with various climaticconditions or the resulting phenotypes of the developing lines, exceptperhaps in a very broad and general fashion. A breeder of ordinary skillin the art would also be unable to recreate the same line twice from thevery same original parents as the breeder is unable to direct how thegenomes combine or how they will interact with the environmentalconditions. This unpredictability results in the expenditure of largeamounts of research resources in the development of a superior new maizeinbred line.

SUMMARY OF THE INVENTION

According to the invention, there is provided a novel inbred maize line,designated PH22G. This invention thus relates to the seeds of inbredmaize line PH22G, to the plants of inbred maize line PH22G, and tomethods for producing a maize plant produced by crossing the inbred linePH22G with itself or another maize line. This invention further relatesto hybrid maize seeds and plants produced by crossing the inbred linePH22G with another maize line.

DEFINITIONS

In the description and examples that follow, a number of terms are usedherein. In order to provide a clear and consistent understanding of thespecification and claims, including the scope to be given such terms,the following definitions are provided. NOTE: ABS is in absolute termsand %MN is percent of the mean for the experiments in which the inbredor hybrid was grown. These designators will follow the descriptors todenote how the values are to be interpreted. Below are the descriptorsused in the data tables included herein.

ANT ROT=ANTHRACNOSE STALK ROT (Colletotrichum graminicola). A 1 to 9visual rating indicating the resistance to Anthracnose Stalk Rot. Ahigher score indicates a higher resistance.

BAR PLT=BARREN PLANTS. The percent of plants per plot that were notbarren (lack ears).

BRT STK=BRITTLE STALKS. This is a measure of the stalk breakage near thetime of pollination, and is an indication of whether a hybrid or inbredwould snap or break near the time of flowering under severe winds. Dataare presented as percentage of plants that did not snap.

BU ACR=YIELD (BUSHELS/ACRE). Yield of the grain at harvest in bushelsper acre adjusted to 15.5% moisture.

CLD TST=COLD TEST. The percent of plants that germinate under cold testconditions.

CLN=CORN LETHAL NECROSIS. Synergistic interaction of maize chloroticmottle virus (MCMV) in combination with either maize dwarf mosaic virus(MDMV-A or MDMV-B) or wheat streak mosaic virus (WSMV). A 1 to 9 visualrating indicating the resistance to Corn Lethal Necrosis. A higher scoreindicates a higher resistance.

COM RST=COMMON RUST (Puccinia sorghi). A 1 to 9 visual rating indicatingthe resistance to Common Rust. A higher score indicates a higherresistance.

D/D=DRYDOWN. This represents the relative rate at which a hybrid willreach acceptable harvest moisture compared to other hybrids on a 1-9rating scale. A high score indicates a hybrid that dries relatively fastwhile a low score indicates a hybrid that dries slowly.

DIP ERS=DIPLODIA EAR MOLD SCORES (Diplodia maydis and Diplodiamacrospora). A 1 to 9 visual rating indicating the resistance toDiplodia Ear Mold. A higher score indicates a higher resistance.

DRP EAR=DROPPED EARS. A measure of the number of dropped ears per plotand represents the percentage of plants that did not drop ears prior toharvest.

D/T=DROUGHT TOLERANCE. This represents a 1-9 rating for droughttolerance, and is based on data obtained under stress conditions. A highscore indicates good drought tolerance and a low score indicates poordrought tolerance.

EAR HT=EAR HEIGHT. The ear height is a measure from the ground to thehighest placed developed ear node attachment and is measured in inches.

EAR MLD=General Ear Mold. Visual rating (1-9 score) where a "1" is verysusceptible and a "9" is very resistant. This is based on overall ratingfor ear mold of mature ears without determining the specific moldorganism, and may not be predictive for a specific ear mold.

EAR SZ=EAR SIZE. A 1 to 9 visual rating of ear size. The higher therating the larger the ear size.

ECB 1LF=EUROPEAN CORN BORER FIRST GENERATION LEAF FEEDING (Ostrinianubilalis). A 1 to 9 visual rating indicating the resistance topreflowering leaf feeding by first generation European Corn Borer. Ahigher score indicates a higher resistance.

ECB 2IT=EUROPEAN CORN BORER SECOND GENERATION INCHES OF TUNNELING(Ostrinia nubilalis). Average inches of tunneling per plant in thestalk.

ECB 2SC=EUROPEAN CORN BORER SECOND GENERATION (Ostrinia nubilalis). A 1to 9 visual rating indicating post flowering degree of stalk breakageand other evidence of feeding by European Corn Borer, Second Generation.A higher score indicates a higher resistance.

ECB DPE=EUROPEAN CORN BORER DROPPED EARS (Ostrinia nubilalis). Droppedears due to European Corn Borer. Percentage of plants that did not dropears under second generation corn borer infestation.

EST CNT=EARLY STAND COUNT. This is a measure of the stand establishmentin the spring and represents the number of plants that emerge on perplot basis for the inbred or hybrid.

EYE SPT=Eye Spot (Kabatiella zeae or Aureobasidium zeae). A 1 to 9visual rating indicating the resistance to Eye Spot. A higher scoreindicates a higher resistance.

FUS ERS=FUSARIUM EAR ROT SCORE (Fusarium moniliforme or Fusariumsubglutinans). A 1 to 9 visual rating indicating the resistance toFusarium ear rot. A higher score indicates a higher resistance.

GDU=Growing Degree Units. Using the Barger Heat Unit Theory, whichassumes that maize growth occurs in the temperature range 50° F.-86° F.and that temperatures outside this range slow down growth; the maximumdaily heat unit accumulation is 36 and the minimum daily heat unitaccumulation is 0. The seasonal accumulation of GDU is a major factor indetermining maturity zones.

GDU SHD=GDU TO SHED. The number of growing degree units (GDUs) or heatunits required for an inbred line or hybrid to have approximately 50percent of the plants shedding pollen and is measured from the time ofplanting. Growing degree units are calculated by the Barger Method,where the heat units for a 24-hour period are: ##EQU1##

The highest maximum temperature used is 86° F. and the lowest minimumtemperature used is 50° F. For each inbred or hybrid it takes a certainnumber of GDUs to reach various stages of plant development.

GDU SLK=GDU TO SILK. The number of growing degree units required for aninbred line or hybrid to have approximately 50 percent of the plantswith silk emergence from time of planting. Growing degree units arecalculated by the Barger Method as given in GDU SHD definition.

GIB ERS=GIBBERELLA EAR ROT (PINK MOLD) (Gibberella zeae). A 1 to 9visual rating indicating the resistance to Gibberella Ear Rot. A higherscore indicates a higher resistance.

GLF SPT=Gray Leaf Spot (Cercospora zeae-maydis). A 1 to 9 visual ratingindicating the resistance to Gray Leaf Spot. A higher score indicates ahigher resistance.

GOS WLT=Goss' Wilt (Corynebacterium nebraskense). A 1 to 9 visual ratingindicating the resistance to Goss' Wilt. A higher score indicates ahigher resistance.

GRN APP=GRAIN APPEARANCE. This is a 1 to 9 rating for the generalappearance of the shelled grain as it is harvested based on such factorsas the color of harvested grain, any mold on the grain, and any crackedgrain. High scores indicate good grain quality.

H/POP=YIELD AT HIGH DENSITY. Yield ability at relatively high plantdensities on 1-9 relative rating system with a higher number indicatingthe hybrid responds well to high plant densities for yield relative toother hybrids. A 1, 5, and 9 would represent very poor, average, andvery good yield response, respectively, to increased plant density.

HC BLT=HELMINTHOSPORIUM CARBONUM LEAF BLIGHT (Helminthosporiumcarbonum). A 1 to 9 visual rating indicating the resistance toHelminthosporium infection. A higher score indicates a higherresistance.

HD SMT=HEAD SMUT (Sphacelotheca reiliana). This score indicates thepercentage of plants not infected.

HSK CVR=HUSK COVER. A 1 to 9 score based on performance relative to keychecks, with a score of 1 indicating very short husks, tip of ear andkernels showing; 5 is intermediate coverage of the ear under mostconditions, sometimes with thin husk; and a 9 has husks extending andclosed beyond the tip of the ear. Scoring can best be done nearphysiological maturity stage or any time during dry down untilharvested. The data is displayed as percent of mean of the experiment.

INC D/A=GROSS INCOME (DOLLARS PER ACRE). Relative income per acreassuming drying costs of two cents per point above 15.5 percent harvestmoisture and current market price per bushel.

INCOME/ACRE. Income advantage of hybrid to be patented over other hybridon per acre basis.

INC ADV=GROSS INCOME ADVANTAGE. GROSS INCOME advantage of variety #1over variety #2.

KSZ DCD=KERNEL SIZE DISCARD. The percent of discard seed; calculated asthe sum of discarded tip kernels and extra large kernels.

L/POP=YIELD AT LOW DENSITY. Yield ability at relatively low plantdensities on a 1-9 relative system with a higher number indicating thehybrid responds well to low plant densities for yield relative to otherhybrids. A 1, 5, and 9 would represent very poor, average, and very goodyield response, respectively, to low plant density.

MDM CPX=MAIZE DWARF MOSAIC COMPLEX (MDMV=Maize Dwarf Mosaic Virus andMCDV=Maize Chlorotic Dwarf Virus). A 1 to 9 visual rating indicating theresistance to Maize Dwarf Mosaic Cornplex. A higher score indicates ahigher resistance.

MST=HARVEST MOISTURE. The moisture is the actual percentage moisture ofthe grain at harvest.

MST ADV=MOISTURE ADVANTAGE. The moisture advantage of variety #1 overvariety #2 as calculated by: MOISTURE of variety #2--MOISTURE of variety#1=MOISTURE ADVANTAGE of variety #1.

NLF BLT=Northern Leaf Blight (Helminthosporium turcicum or Exserohilumturcicum). A 1 to 9 visual rating indicating the resistance to NorthernLeaf Blight. A higher score indicates a higher resistance.

PLT HT=PLANT HEIGHT. This is a measure of the height of the plant fromthe ground to the tip of the tassel in inches.

POL SC=POLLEN SCORE. A 1 to 9 visual rating indicating the amount ofpollen shed. The higher the score the more pollen shed.

POL WT=POLLEN WEIGHT. This is calculated by dry weight of tasselscollected as shedding commences minus dry weight from similar tasselsharvested after shedding is complete.

It should be understood that the inbred can, through routinemanipulation of cytoplasmic or other factors, be produced in amale-sterile form. Such embodiments are also contemplated within thescope of the present claims.

POP K/A=PLANT POPULATIONS. Measured as 1000s per acre.

POP ADV=PLANT POPULATION ADVANTAGE. The plant population advantage ofvariety #1 over variety #2 as calculated by PLANT POPULATION of variety#2--PLANT POPULATION of variety #1=PLANT POPULATION ADVANTAGF of variety#1.

PRM=PREDICTED RELATIVE MATURITY. This trait, predicted relativematurity, is based on the harvest moisture of the grain. The relativematurity rating is based on a known set of checks and utilizes standardlinear regression analyses and is also referred to as the ComparativeRelative Maturity Rating System that is similar to the MinnesotaRelative Maturity Rating System.

PRM SHD=A relative measure of the growing degree units (GDU) required toreach 50% pollen shed. Relative values are predicted values from thelinear regression of observed GDU's on relative maturity of commercialchecks.

RT LDG=ROOT LODGING. Root lodging is the percentage of plants that donot root lodge; plants that lean from the vertical axis at anapproximately 30° angle or greater would be counted as root lodged.

RTL ADV=ROOT LODGING ADVANTAGE. The root lodging advantage of variety #1over variety #2.

SCT GRN=SCATTER GRAIN. A 1 to 9 visual rating indicating the amount ofscatter grain (lack of pollination or kernel abortion) on the ear. Thehigher the score the less scatter grain.

SDG VGR=SEEDLING VIGOR. This is the visual rating (1 to 9) of the amountof vegetative growth after emergence at the seedling stage(approximately five leaves). A higher score indicates better vigor.

SEL IND=SELECTION INDEX. The selection index gives a single measure ofthe hybrid's worth based on information for up to five traits. A maizebreeder may utilize his or her own set of traits for the selectionindex. One of the traits that is almost always included is yield. Theselection index data presented in the tables represent the mean valueaveraged across testing stations.

SLF BLT=SOUTHERN LEAF BLIGHT (Helminthosporium maydis or Bipolarismaydis). A 1 to 9 visual rating indicating the resistance to SouthernLeaf Blight. A higher score indicates a higher resistance.

SOU RST=SOUTHERN RUST (Puccinia polysora). A 1 to 9 visual ratingindicating the resistance to Southern Rust. A higher score indicates ahigher resistance.

STA GRN=STAY GREEN. Stay green is the measure of plant health near thetime of black layer formation (physiological maturity). A high scoreindicates better late-season plant health.

STD ADV=STALK STANDING ADVANTAGE. The advantage of variety #1 overvariety #2 for the trait STK CNT.

STK CNT=NUMBER OF PLANTS. This is the final stand or number of plantsper plot.

STK LDG=STALK LODGING. This is the percentage of plants that did notstalk lodge (stalk breakage) as measured by either natural lodging orpushing the stalks and determining the percentage of plants that breakbelow the ear.

STW WLT=Stewart's Wilt (Erwinia stewartii). A 1 to 9 visual ratingindicating the resistance to Stewart's Wilt. A higher score indicates ahigher resistance.

TAS BLS=TASSEL BLAST. A 1 to 9 visual rating was used to measure thedegree of blasting (necrosis due to heat stress) of the tassel at thetime of flowering. A 1 would indicate a very high level of blasting attime of flowering, while a 9 would have no tassel blasting.

TAS SZ=TASSEL SIZE. A 1 to 9 visual rating was used to indicate therelative size of the tassel. The higher the rating the larger thetassel.

TAS WT=TASSEL WEIGHT. This is the average weight of a tassel (grams)just prior to pollen shed.

TEX EAR=EAR TEXTURE. A 1 to 9 visual rating was used to indicate therelative hardness (smoothness of crown) of mature grain. A 1 would bevery soft (extreme dent) while a 9 would be very hard (flinty or verysmooth crown).

TILLER=TILLERS. A count of the number of tillers per plot that couldpossibly shed pollen was taken. Data are given as a percentage oftillers: number of tillers per plot divided by number of plants perplot.

TST WT=TEST WEIGHT (UNADJUSTED). The measure of the weight of the grainin pounds for a given volume (bushel).

TST WTA=TEST WEIGHT ADJUSTED. The measure of the weight of the grain inpounds for a given volume (bushel) adjusted for 15.5 percent moisture.

TSW ADV=TEST WEIGHT ADVANTAGE. The test weight advantage of variety #1over variety #2.

WIN M%=PERCENT MOISTURE WINS.

WIN Y%=PERCENT YIELD WINS.

YLD=YIELD. It is the same as BU ACR ABS.

YLD ADV=YIELD ADVANTAGE. The yield advantage of variety #1 over variety#2 as calculated by: YIELD of variety #1--YIELD variety #2=yieldadvantage of variety #1.

YLD SC=YIELD SCORE. A 1 to 9 visual rating was used to give a relativerating for yield based on plot ear piles. The higher the rating thegreater visual yield appearance.

DETAILED DESCRIPTION OF THE INVENTION

Inbred maize lines are typically developed for use in the production ofhybrid maize lines. Inbred maize lines need to be highly homogeneous,homozygous and reproducible to be useful as parents of commercialhybrids. There are many analytical methods available to determine thehomozygotic and phenotypic stability of these inbred lines.

The oldest and most traditional method of analysis is the observation ofphenotypic traits. The data is usually collected in field experimentsover the life of the maize plants to be examined. Phenotypiccharacteristics most often observed are for traits associated with plantmorphology, ear and kernel morphology, insect and disease resistance,maturity, and yield.

In addition to phenotypic observations, the genotype of a plant can alsobe examined. There are many laboratory-based techniques available forthe analysis, comparison and characterization of plant genotype; amongthese are Isozyme Electrophoresis, Restriction Fragment LengthPolymorphisms (RFLPs), Randomly Amplified Polymorphic DNAs (RAPDs),Arbitrarily Primed Polymerase Chain Reaction (AP-PCR), DNA AmplificationFingerprinting (DAF), Sequence Characterized Amplified Regions (SCARs),Amplified Fragment Length Polymorphisms (AFLPs), and Simple SequenceRepeats (SSRs) which are also referred to as Microsatellites.

The most widely used of these laboratory techniques are IsozymeElectrophoresis and RFLPs as discussed in Lee, M., "Inbred Lines ofMaize and Their Molecular Markers," The Maize Handbook,(Springer-Verlag, N.Y. Inc. 1994, at 423-432) incorporated herein byreference. Isozyme Electrophoresis is a useful tool in determininggenetic composition, although it has relatively low number of availablemarkers and the low number of allelic variants among maize inbreds.RFLPs have the advantage of revealing an exceptionally high degree ofallelic variation in maize and the number of available markers is almostlimitless.

Maize RFLP linkage maps have been rapidly constructed and widelyimplemented in genetic studies. One such study is described inBoppenmaier, et al., "Comparisons among strains of inbreds for RFLPs",Maize Genetics Cooperative Newsletter, 65:1991, pg. 90, is incorporatedherein by reference. This study used 101 RFLP markers to analyze thepatterns of 2 to 3 different deposits each of five different inbredlines. The inbred lines had been selfed from 9 to 12 times before beingadopted into 2 to 3 different breeding programs. It was results fromthese 2 to 3 different breeding programs that supplied the differentdeposits for analysis. These five lines were maintained in the separatebreeding programs by selfing or sibbing and rogueing off-type plants foran additional one to eight generations. After the RFLP analysis wascompleted, it was determined the five lines showed 0-2% residualheterozygosity. Although this was a relatively small study, it can beseen using RFLPs that the lines had been highly homozygous prior to theseparate strain maintenance.

Inbred maize line PH22G is a yellow, dent maize inbred that is bestsuited as a female in crosses for producing first generation F₁ maizehybrids, but can also be used as a male in hybrid production. Inbredmaize line PH22G is best adapted to the Northwest, Northcentral andNortheast Corn Belt regions of the United States and the Corn Beltregions of Canada and Hungary and can be used to produce hybrids fromapproximately 93 relative maturity based on the Comparative RelativeMaturity Rating System for harvest moisture of grain. Inbred maize linePH22G demonstrates very good stay green, excellent roots and goodbrittle stalk tolerance. Inbred maize line PH22G also demonstratesexcellent grain quality and excellent husk cover. Inbred PH22G has amedium green leaf color with purple anthocyanin striping on the stalkinternodes. In hybrid combination, PH22G demonstrates high, stableyields, and good dry down. In hybrid combination, PH22G alsodemonstrates acceptable roots, very good stalks, good grain quality,very good silage traits, excellent resistance to Brittle Stalk andexcellent husk cover. For its area of adaptation, PH22G hybridsdemonstrate high yield, good dry down, very good stalks, very goodresistance to Brittle Stalk and acceptable roots. For its area ofadaptation, PH22G also demonstrates excellent seedling vigor and earlygrowth, good grain quality and excellent husk cover.

The inbred has shown uniformity and stability within the limits ofenvironmental influence for all the traits as described in the VarietyDescription Information (Table 1) that follows. The inbred has beenself-pollinated and ear-rowed a sufficient number of generations withcareful attention paid to uniformity of plant type to ensure thehomozygosity and phenotypic stability necessary to use in commercialproduction. The line has been increased both by hand and in isolatedfields with continued observation for uniformity. No variant traits havebeen observed or are expected in PH22G.

Inbred maize line PH22G, being substantially homozygous, can bereproduced by planting seeds of the line, growing the resulting maizeplants under self-pollinating or sib-pollinating conditions withadequate isolation, and harvesting the resulting seed, using techniquesfamiliar to the agricultural arts.

                                      TABLE 1    __________________________________________________________________________    VARIETY DESCRIPTION INFORMATION    VARIETY = PH22G    __________________________________________________________________________      TYPE: (describe intermediate types in Comments section):    2   1 = Sweet 2 = Dent 3 = Flint 4 = Flour 5 = Pop 6 = Ornamental      MATURITY:    DAYS   HEAT UNITS    064    1,244.5                  From emergence to 50% of plants in silk    064    1,247.0                  From emergence to 50% of plants in pollen    004    0,095.8                  From 10% to 90% pollen shed    068    1,331.8                  From 50% silk to harvest at 25% moisture      PLANT:                                     Standard                                          Sample                                     Deviation                                          Size    0,175.0          cm Plant Height (to tassel tip)                                     8.87  4    0,077.3          cm Ear Height (to base of top ear node)                                     6.40  4    0,111.6          cm Length of Top Ear Internode                                     1.21 20    1        Average Number of Tillers                                     0.50  4    1.0      Averge Number of Ears per Stalk                                     0.00  4    2.9      Anthocyanin of Brace Roots: 1 = Absent 2 = Faint 3 = Moderate 4             = Dark      LEAF:                                     Standard                                          Sample                                     Deviation                                          Size    009.1 cm Width of Ear Node Leaf   0.82                                          20    063.0 cm Length of Ear Node Leaf  4.58                                          20    05.8     Number of leaves above top ear                                      1.37                                          20    039.3    Degrees Leaf Angle (measure from 2nd leaf above                                     11.09                                           4             ear at anthesis to stalk above leaf)    03       Leaf Color                  Dark Green                        (Munsell code)   5GY36    1.0      Leaf Sheath Pubescence (Rate on scale from 1 = none to 9 = like             peach fuzz)    6.3      Marginal Waves (Rate on scale from 1 = none to 9 = many)    6.5      Longitudinal Creases (Rate on scale from 1 = none to 9 = many)      TASSEL:                                     Standard                                          Sample                                     Deviation                                          Size    04.2     Number of Primary Lateral Branches                                      0.38                                          20    053.3    Branch Angle from Central Spike                                     20.19                                           4    47.7  cm Tassel Length (from top leaf collar to tassel tip)                                     3.20  4    6.8      Pollen Shed (rate on scale from 0 = male sterile to 9 = heavy             shed)    07       Anther Color                   Yellow                        (Munsell code)   7.5Y8.56    17       Glume Color                   Purple                        (Munsell code)   5R34    2.0      Bar Glumes (Glume Bands): 1 = Absent 2 = Present    20       Peduncle Length (cm. fmm top leaf to basel branches)    6a.      EAR (Unhusked Data):    1     Silk Color (3 days after emergence)                                Light Green                                        (Munsell code)                                                10Y96    2     Fresh Husk Color (25 days after 50% silking)                                Medium Green                                        (Munsell code)                                                5GY68    21    Dry Husk Color (65 days after 50% silking)                                Buff    (Munsell code)                                                2.5Y8.54          Position of Ear at Dry Husk Stage: 1 = Upright 2 = Horizontal 3 =          Pendant    6     Husk Tightness (Rate of Scale from 1 = very loose to 9 = very          tight)    2     Husk Extension (at harvest): 1 = Short (ears exposed) 2 = Medium          (<8 cm)          3 = Long (8-10 cm beyond eartip) 4 = Very Long (>10                                                Medium    6b.      EAR (Husked Ear Data):                                     Standard                                          Sample                                     Deviation                                          Size    14    cm Ear Length               1.04                                          20    40    mm Ear Diameter at mid-point                                      1.06                                          20    105   gm Ear Weight              19.59                                          20    12       Number of Kernal Rows    0.47                                          20    2        Kernal Rows: 1 = Indistinct 2 = Distinct                                                Distinct    1        Row Alignment: 1 = Straight 2 = Slightly Curved 3                                                Straight    11    cm Shank Length             4.06                                          20    2        Ear Taper: 1 = Slight 2 = Average 3 = Extreme                                                Average      KERNEL (Dried):                                     Standard                                          Sample                                     Deviation                                          Size    11    mm Kernal Length           0.47 20    9     mm Kernal Width            0.25 20    4     mm Kernal Thickness        0.20 20    28       % Round Kernals (Shape Grade)                                     4.64  4    1        Aleurone Color Pattern: 1 = Homozygous 2 = Segregating                                                Homozygous    7        Aluerone Color                       Yellow        (Munsell code)                                                2.5Y812    7        Hard Endosperm Color                       Yellow        (Munsell code)                                                2.5Y812    3        Endosperm Type:                       Normal Starch             1 = Sweet (Su1) 2 = Extra Sweet (sh2) 3 = Normal Starch             4 = High Amylose Starch 5 = Waxy Starch 6 = High Protein             7 = High Lysine 8 = Super Sweet (se) 9 = High Oil             10 = Other.sub.------    29    gm Weight per 100 Kernels (unsized sample)                                     3.50  4      COB:                                     Standard                                          Sample                                     Deviation                                          Size    23    mm Cob Diameter at mid-point                                     1.56 20    14       Cob Color Red           (Munsell code)                                                2.5YR56    2        Cob Strength 1 = Weak 2 = Strong      DISEASE RESISTANCE (Rate from 1 (most susceptible) to 9 (most      resistant); leave blank      if not tested; leave Race or Strain Options blank if polygenic):    A. Leaf Blights, Wilts, and Local Infection Diseases          Anthracnose Leaf Blight ( Colletotrichum graminicola)          Common Rust (Puccinia sorghi)          Common Smut (Ustilago          maydis) Eyespot (Kabatiella zeae)    7     Goss's Wilt (Clavibacter michiganense spp. nebraskense)    3     Gray Leaf Spot (Cercospora zeae-maydis)          Helminthosporium Leaf Spot (Bipolaris zeicola) Race----    6     Northern Leaf Blight (Exserohilum turcicum) Race----          Southern Leaf Blight (Bipolaris maydis) Race----          Southern Rust (Puccinia polysora)    5     Stewart's Wilt (Erwinia stewartii)          Other(Specify)----    B. Systemic Diseases    Corn Lethal Necrosis (MCMV and MDMV)    Head Smut (Sphacelotheca reiliana)    Maize Chlorotic Dwarf Virus (MDV)    Maize Chlorotic Mottle Virus (MCMV)    Maize Dwarf Mosaic Virus (MDMV)    Sorghum Downy Mildew of Corn (Peronosclerospora sorghi)    Other (Specify)----    C. Stalk Rots    Anthracnose Stalk Rot (Colletotrichum graminicola)    Dipiodia Stalk Rot (Stenocarpella maydis)    Fusarium Stalk Rot (Fusarium moniliforme)    Gibberella Stalk Rot (Gibberella zeae)    Other (Specify)----    D. Ear and Kernel Rats          Aspergillus Ear and Kernal Rot (Aspergillus flavus)          Diplodia Ear Rot (Stenocarpella maydis)          Fusarium Ear and Kernel Rot (Fusarium moniliforme)    4     Gibberella Ear Rot (Gibberella zeae)          Other (Specify)----          Banks grass Mite (Oligonychus pratensis)          Corn Worm (Helicoverpa zea)          Leaf Feeding          Silk Feeding           mg larval wt.          Ear Damage          Corn Leaf Aphid (Rhopalosiphum maidis)          Corn Sap Beetle (Carpophilus dimidiatus          European Corn Borer (Ostrinia nubilalis)    3     1st Generation (Typically Whorf Leaf Feeding)    6     2nd Generation (Typically Leaf Sheath-Collar Feeding)          Stalk Tunneling          cm tunneled/plant          Fall Armyworm (Spodoptera fruqiperda)          Leaf Feeding          Silk Feeding          mg larval wt.          Maize Weevil (Sitophilus zeamaize          Northern Rootworm (Diabrotica barberi)          Southern Rootworm (Diabrotica undecimpunctata)          Southwestern Corn Borer (Diatreaea grandiosella)          Leaf Feeding          Stalk Tunneling          cm tunneled/plant          Two-spotted Spider Mite (Tetranychus urticae)          Western Rootworm (Diabrotica virgifrea virgifera)          Other (Specify)----      AGRONOMIC TRAITS:    4    Staygreen (at 65 days after arthesis) (Rate on a scale from 1 =         worst to         excellent)    0.0  % Dropped Ears (at 65 days after anthesis)         % Pre-anthesis Brittle Snapping         % Pre-anthesis Root Lodging    4.4  Post-anthesis Root Lodging (at 65 days after anthesis)    5,100         Kg/ha Yield (at 12-13% grain moisture)    __________________________________________________________________________     *In interpreting the foregoing color designations, reference may be had t     the Munsell Glossy Book of Color, a standard color reference.

INDUSTRIAL APPLICABILITY

This invention also is directed to methods for producing a maize plantby crossing a first parent maize plant with a second parent maize plantwherein either the first or second parent maize plant is an inbred maizeplant of the line PH22G. Further, both first and second parent maizeplants can come from the inbred maize line PH22G. Thus, any such methodsusing the inbred maize line PH22G are part of this invention: selfing,backcrosses, hybrid production, crosses to populations, and the like.All plants produced using inbred maize line PH22G as a parent are withinthe scope of this invention. Advantageously, the inbred maize line isused in crosses with other, different, maize inbreds to produce firstgeneration (F₁) maize hybrid seeds and plants with superiorcharacteristics.

As used herein, the term plant includes plant cells, plant protoplasts,plant cell tissue cultures from which maize plants can be regenerated,plant calli, plant clumps, and plant cells that are intact in plants orparts of plants, such as embryos, pollen, ovules, flowers, kernels,ears, cobs, leaves, husks, stalks, roots, root tips, anthers, silk andthe like.

Duncan, Williams, Zehr, and Widholm, Planta (1985) 165:322-332 reflectsthat 97% of the plants cultured that produced callus were capable ofplant regeneration. Subsequent experiments with both inbreds and hybridsproduced 91% regenerable callus that produced plants. In a further studyin 1988, Songstad, Duncan & Widholm in Plant Cell Reports (1988),7:262-265 reports several media additions that enhance regenerability ofcallus of two inbred lines. Other published reports also indicated that"nontraditional" tissues are capable of producing somatic embryogenesisand plant regeneration. K. P. Rao, et al., Maize Genetics CooperationNewsletter, 60:64-65 (1986), refers to somatic embryogenesis from glurnecallus cultures and B. V. Conger, et al., Plant Cell Reports, 6:345-347(1987) indicates somatic embryogenesis from the tissue cultures of maizeleaf segments. Thus, it is clear from the literature that the state ofthe art is such that these methods of obtaining plants are, and were,"conventional" in the sense that they are routinely used and have a veryhigh rate of success.

Tissue culture of maize is described in European Patent Application,publication 160,390, incorporated herein by reference. Maize tissueculture procedures are also described in Green and Rhodes, "PlantRegeneration in Tissue Culture of Maize," Maize for Biological Research(Plant Molecular Biology Association, Charlottesville, Va. 1982, at367-372) and in Duncan, et al., "The Production of Callus Capable ofPlant Regeneration from Immature Embryos of Numerous Zea MaysGenotypes," 165 Planta 322-332 (1985). Thus, another aspect of thisinvention is to provide cells which upon growth and differentiationproduce maize plants having the physiological and morphologicalcharacteristics of inbred line PH22G.

Maize is used as human food, livestock feed, and as raw material inindustry. The food uses of maize, in addition to human consumption ofmaize kernels, include both products of dry- and wet-milling industries.The principal products of maize dry milling are grits, meal and flour.The maize wet-milling industry can provide maize starch, maize syrups,and dextrose for food use. Maize oil is recovered from maize germ, whichis a by-product of both dry-and wet-milling industries.

Maize, including both grain and non-grain portions of the plant, is alsoused extensively as livestock feed, primarily for beef cattle, dairycattle, hogs, and poultry.

Industrial uses of maize include production of ethanol, maize starch inthe wet-milling industry and maize flour in the dry-milling industry.The industrial applications of maize starch and flour are based onfunctional properties, such as viscosity, film formation, adhesiveproperties, and ability to suspend particles. The maize starch and flourhave application in the paper and textile industries. Other industrialuses include applications in adhesives, building materials, foundrybinders, laundry starches, explosives, oil-well muds, and other miningapplications.

Plant parts other than the grain of maize are also used in industry: forexample, stalks and husks are made into paper and wallboard and cobs areused for fuel and to make charcoal.

The seed of inbred maize line PH22G, the plant produced from the inbredseed, the hybrid maize plant produced from the crossing of the inbred,hybrid seed, and various parts of the hybrid maize plant can be utilizedfor human food, livestock feed, and as a raw material in industry.

PERFORMANCE EXAMPLES OF PH22G

In the examples that follow, the traits and characteristics of inbredmaize line PH22G are presented as an inbred per se and in hybridcombination. The data collected on inbred maize line PH22G is presentedfor key characteristics and traits.

Inbred Comparisons

The results in Table 2A compare inbred PH22G to inbred PHEM9. Theresults show that both inbreds have above average stay green scores.Inbred PH22G demonstrates excellent brittle stalk resistance and hasbetter brittle stalk resistance than inbred PHEM9. Inbred PH22G showsexcellent Head Smut resistance.

The results in Table 2B compare inbred PH22G to inbred PHRE1. Theresults show that both inbreds have above average yields. Inbred PH22Gexhibits better root lodging resistance and stay green than inbredPHRE1. Inbred PH22G presents very good grain appearance andsignificantly better ear texture than inbred PHRE1. Inbred PH22G showsexcellent Head Smut resistance.

The results in Table 2C compare inbred PH22G to inbred PH19E. Theresults show that both inbreds have above average yields. Inbred PH22Gexhibits very good grain appearance, very good resistance to rootlodging and excellent brittle stalk resistance. Inbred PH22G showsexcellent Head Smut resistance.

Inbred By Tester Comparisons

The results in Table 3 compare the inbred PH22G and inbred PH19E, wheneach inbred is crossed to the same tester lines. Both the PH22G and thePH19E hybrids exhibit above average yields, with the PH22G hybridsyielding better than the PH19E hybrids. The PH22G hybrids demonstratesignificantly lower harvest moisture than the PH19E hybrids. Both thePH22G and the PH19E hybrids show above average resistance to stalklodging. The PH22G hybrids demonstrate better resistance to root lodgingand brittle stalk than the PH19E hybrids.

Hybrid Comparisons

The results in Table 4A compare inbred PHDN7 crossed to PH22G and inbredPHAA0 crossed to PHTD5. The results show that both hybrids have aboveaverage yields and the PHDN7/PH22G hybrid demonstrates a significantlyhigher yield than the PHAA0/PHTD5 hybrid. The PHDN7/PH22G hybridexhibits above average seedling vigor. The PHDN7/PH22G hybrid exhibitssignificantly greater plant and ear height than the PHAA0/PHTD5 hybrid.The PHDN7/PH22G hybrid demonstrates above average resistance to stalklodging and shows above average and significantly better resistance tobrittle stalk than the PHAA0/PHTD5 hybrid. The PHDN7/PH22G hybridexhibits above average grain appearance.

The results in Table 4B compare inbred PHDN7 crossed to PH22G and inbredPHEM9 crossed to PHR25. The results show that the PHDN7/PH22G hybriddemonstrates an above average yield and significantly higher yield thanthe PHEM9/PHR25 hybrid. The PHDN7/PH22G hybrid exhibits above averageplant height and significantly higher ear height than the PHEM9/PHR25hybrid. The PHDN7/PH22G hybrid exhibits above average resistance tostalk lodging and brittle stalk.

The results in Table 4C compare inbred PHDN7 crossed to PH22G and inbredPHM10 crossed to PHN37. The results show that both hybrids have aboveaverage yields and the PHDN7/PH22G hybrid demonstrates a significantlyhigher yield than the PHM10/PHN37 hybrid. The PHDN7/PH22G hybridexhibits above average seedling vigor. The PHDN7/PH22G hybriddemonstrates above average and significantly better resistance to stalklodging than the PHMIO/PHN37 hybrid. The PHDN7/PH22G hybrid exhibitsabove average and significantly better resistance to brittle stalk thanthe PHM10/PHN37 hybrid. The PHDN7/PH22G hybrid exhibits above averagegrain appearance. The PHDN7 /PH22G hybrid exhibits above average plantheight and significantly higher ear height than the PHM10/PHN37 hybrid.

The results in Table 5A compare inbred PHDN7 crossed to inbred PH22G andinbred PHAA0 crossed to inbred PHTD5. The PHDN7/PH22G hybrid producesmore tonnage of silage than the PHAA0/PHTD5 hybrid.

The results in Table 5B compare inbred PHDN7 crossed to inbred PH22G andinbred PHN37 crossed to inbred PHMIO. The PHDN7/PH22G hybrid producesmore tonnage of silage than the PHN37/PHM10 hybrid.

The results in Table 6A compare inbred PHDN7 crossed to inbred PH22G andinbred PHAA0 crossed to inbred PHBF0. The PHDN7/PH22G hybrid producesabove average and greater husk cover than the PHAA0/PHBF0 hybrid.

The results in Table 6B compare inbred PHDN7 crossed to inbred PH22G andinbred PHP02 crossed to inbred PHTM9. The PHDN7/PH22G hybrid producesabove average and greater husk cover than the PHP02/PHTM9 hybrid.

The results in Table 6C compare inbred PHDN7 crossed to inbred PH22G andinbred PHAA0 crossed to inbred PHTD5. The PHDN7/PH22G hybrid producesabove average and significantly greater husk cover than the PHAA0/PHTD5hybrid.

The results in Table 6D compare inbred PHDN7 crossed to inbred PH22G andinbred PHRE1 crossed to inbred PHTD5. The PHDI N7/PH22G hybrid producesabove average and significantly greater husk cover than the PHRE1/PHTD5hybrid.

                                      TABLE 2A    __________________________________________________________________________    PAIRED INBRED COMPARISON REPORT    VARIETY #1 = PH22G    VARIETY #2 = PHEM9    __________________________________________________________________________               SDG EST TIL GDU  GDU  POL TAS                                            TAS PLT               VGR CNT LER SHD  SLK  SC  BLS                                            SZ  MT               ABS ABS ABS ABS  ABS  ABS ABS                                            ABS ABS    __________________________________________________________________________    TOTAL SUM           1   5.7 34.5                       1.5 113.7                                114.0                                     4.7 9.0                                            4.6 69.6           2   5.6 29.1                       5.7 114.9                                115.5                                     5.9 9.0                                            6.1 70.7           LOCS               17  22  18  32   32   10  1  14  20           REFS               17  22  iB  32   32   10  1  14  20           DIFF               0.1 5.5 4.2 1.2  1.5  1.2 0.0                                            1.4 1.1           PR > T               .718                   .074*                       .181                           .097*                                .043+                                     .009#  .000#                                                .483    __________________________________________________________________________                EAR RT   STA                            STK BRT SCT EAR                                           TEX  EAR                HT  LDG  GRN                            LDG STK GRN SZ EAR  MLD                ABS ABS  ABS                            ABS ABS ABS ABS                                           ABS  ABS    __________________________________________________________________________    TOTAL SUM           1    30.9                    90.2 6.0                            100.0                                100.0                                    7.3 6.0                                           6.0  6.6           2    27.4                    99.2 6.3                            100.0                                93.4                                    8.5 6.5                                           6.0  8.0           LOCS 18  5    3  1   2   4   2  3    5           REFS 18  5    3  1   2   4   2  3    5           DIFF 3.5 9.0  0.3                            0.0 6.6 1.3 0.5                                           0.0  1.4           PR > T                .002#                    .374 .423   .226                                    .141                                        .500                                           .999 .052*    __________________________________________________________________________                    BAR NLF         HD  ECB                    FLT BLT         SMT 1LF                    ABS ABS         ABS ABS    __________________________________________________________________________    TOTAL SUM           1        100.0                        8.0         100.0                                        2.0           2        97.8                        8.5         98.3                                        4.0           LOCS     6   2           2   1           REFS     6   2           4   1           DIFF     2.2 0.5         1.7 2.0           PR > T   .210                        .500        .500    __________________________________________________________________________     * = 10% SIG     + = 5% SIG     # = 1% SIG

                                      TABLE 2B    __________________________________________________________________________    PAIRED INBRED COMPARISON REPORT    VARIETY #1 = PH22G    VARIETY #2 = PHRE1    __________________________________________________________________________               BU  BU      TST SDG EST TIL GDU  GDU               ACR ACR MST WT  VGR CNT LER SHD  SLK               ABS % MN                       ABS ABS ABS ABS ABS ABS  ABS    __________________________________________________________________________    TOTAL SUM           1   80.4                   111 19.5                           57.4                               5.1 41.6                                       2.6 120.1                                                119.7           2   72.0                   100 18.7                           57.9                               5.8 41.1                                       1.7 114.4                                                114.5           LOCS               28  28  33  24  52  90  72  109  105           REPS               53  53  57  44  59  138 92  124  116           DIFF               8.4 11  0.8 0.5 0.6 0.5 0.9 5.6  5.1           PR > T               .033+                   .125                       .038+                           .013+                               .003#                                   .364                                       .181                                           .00# .000#    __________________________________________________________________________               POL POL POL  TAS TAS PLT EAR  RT  STA               WT  WT  SC   BLS SZ  HT  HT   LDG GRN               ABS % MN                       ABS  ABS ABS ABS ABS  ABS ABS    __________________________________________________________________________    TOTAL SUM           1   100.6                   76  5.0  8.8 4.5 69.1                                        31.4 95.0                                                 4.8           2   106.4                   82  5.3  8.9 4.4 62.8                                        26.6 72.2                                                 3.6           LOCS               26  26  22   4   33  55  47   11  10           REPS               34  34  26   6   34  66  57   12  13           DIFF               5.8 6   0.3  0.1 0.0 6.4 4.8  22.7                                                 1.3           PR > T               .397                   .288                       .394 .638                                .999                                    .000#                                        .000#                                             .012+                                                 .028+    __________________________________________________________________________               STK BRT  GRN SCT EAR TEX EAR BAR  DRP               LDG STK  APP GRN SZ  EAR MLD PLT  EAR               ABS ABS  ABS ABS ABS ABS ABS ABS  ABS    __________________________________________________________________________    TOTAL SUM           1   95.7                   100.0                        7.6 7.7 5.7 6.5 6.8 98.4 99.8           2   95.0                   97.2 7.1 7.2 5.0 4.7 7.2 97.6 100.0           LOCS               20  6    14  9   3   6   12  41   16           REPS               34  7    24  10  3   6   14  48   29           DIFF               0.7 2.8  0.5 0.4 0.7 1.8 0.5 0.8  0.1           PR > T               .704                   .175 .125                            .347                                .184                                    .000#                                        .457                                            .430 .215    __________________________________________________________________________               GLF NLF  GDS STW   HD  GIB   ECB ECB               SPT BLT  WLT WLT   SMT ERS   1LF 2SC               ABS ABS  ABS ABS   ABS ABS   ABS ABS    __________________________________________________________________________    TOTAL SUM           1   3.3 6.5  6.8 4.5   99.6                                      3.6   3.3 6.0           2   5.0 6.5  7.5 6.5   98.9                                      4.6   3.3 2.3           LOCS               2   8    2   1     5   4     4   1           REPS               4   12   4   2     12  8     4   2           DIFF               1.8 0.0  0.8 2.0   0.7 1.0   0.0 3.7           PR > T               .090*                   .999 .500      .281                                      .161  .999    __________________________________________________________________________     * = 10% SIG     + = 5% SIG     # = 1% SIG

                                      TABLE 2C    __________________________________________________________________________    PAIRED INBRED COMPARISON REPORT    VARIETY #1 = PH22G    VARIETY #2 = PH19E    __________________________________________________________________________               BU  BU      TST SDG EST TIL GDU  GDU               ACR ACR MST WT  VGR CNT LER SHD  SLK               ABS % MN                       ABS ABS ABS ABS ABS ABS  ABS    __________________________________________________________________________    TOTAL SUM           1   81.8                   110 20.4                           57.4                               5.2 44.2                                       1.9 117.7                                                117.1           2   81.5                   108 20.9                           57.2                               5.9 40.9                                       2.3 115.8                                                118.0           LOCS               26  26  28  23  40  56  43  73   69           REPS               49  49  50  41  47  92  56  80   72           DIFF               0.2 2   0.4 0.1 0.7 3.3 0.4 1.9  0.8           PR > T               .910                   .674                       .298                           .610                               .016+                                   .086*                                       .640                                           .000#                                                .105    __________________________________________________________________________               POL POL POL TAS TAS  PLT EAR RT  STA               WT  WT  SC  BLS SZ   HT  HT  LDG GRN               ABS % MN                       ABS ABS ABS  ABS ABS ABS ABS    __________________________________________________________________________    TOTAL SUM           1   89.8                   76  5.0 9.0 4.5  69.8                                        32.0                                            94.4                                                4.1           2   93.3                   78  5.8 9.0 5.2  72.4                                        31.6                                            93.4                                                4.2           LOCS               11  11  13  2   24   42  39  10  8           REPS               11  11  13  2   25   52  48  11  11           DIFF               3.5 2   0.8 0.0 0.7  2.6 0.3 1.1 0.1           PR > T               .790                   .872                       .119                           .999                               .018+                                    .002#                                        .651                                            .696                                                .897    __________________________________________________________________________               STK BRT GRN SCT  EAR TEX EAR BAR DRP               LDG STK AFF GRN  SZ  EAR MLD PLT EAR               ABS ABS ABS ABS  ABS ABS ABS ABS ABS    __________________________________________________________________________    TOTAL SUM           1   96.0                   100.0                       7.5 8.2  5.7 6.2 6.8 99.1                                                99.8           2   98.1                   98.5                       7.2 7.7  6.7 6.2 7.5 98.8                                                99.9           LOCS               17  5   12  6    3   5   10  27  14           REPS               30  5   21  7    3   5   12  34  27           DIFF               2.1 1.5 0.3 0.5  1.0 0.0 0.7 0.3 0.1           PR > T               .034+                   .374                       .180                           .203 .225                                    .999                                        .297                                            .623                                                .172    __________________________________________________________________________               GLF                  NLF   GOS STW  HD  GIB   ECB ECB               SPT                  BLT   WLT WLT  SMT ERS   1LF 2SC               ABS                  ABS   ABS ABS  ABS ABS   ABS ABS    __________________________________________________________________________    TOTAL SUM           1   3.0                  6.3   6.8 4.5  99.5                                     4.0   2.3 6.0           2   3.0                  5.1   8.0 6.0  95.2                                     4.0   5.3 5.0           LOCS               1  6     2   1    4   2     3   1           REPS               2  9     4   2    8   4     3   2           DIFF               0.0                  1.3   1.3 1.5  4.3 0.0   3.0 1.0           PR > T .136  .344     .276                                     .999  .188    __________________________________________________________________________     * = 10% SIG     + = 5% SIG     # = 1% SIG

                                      TABLE 3    __________________________________________________________________________    Average Inbred By Tester Performance Comparing PH22G To PH19E Crossed    To The Same Inbred Testers And Grown In The Same Experiments.    __________________________________________________________________________               SEL     BU  BU  PRM     TST SDG EST GDU               IND PRM ACR ACR SHD MST WT  VGR CNT SHD               % MN                   ABS ABS % MN                               ABS % MN                                       ABS % MN                                               % MN                                                   % MN    __________________________________________________________________________    TOTAL SUM           REPS               10  12  87  87  8   112 53  94  105 31           LOCS               10  12  74  74  8   99  42  78  86  25           PH22G               100 89  137 105 92  98  53  106 101 100           PH19E               96  91  133 102 91  101 54  108 100 100           DIFF               4   2   4   3   0   3   1   1   0   1           PR > T               0.15                   0.16                       0.06                           0.03                               0.99                                   0.00                                       0.00                                           0.60                                               0.99                                                   0.13    __________________________________________________________________________               GDU STK PLT EAR RT  STA STK BRT GRN ECB               SLK CNT HT  HT  LDG GRN LDG STK APP DPE               % MN                   % MN                       % MN                           % MN                               % MN                                   % MN                                       % MN                                           % MN                                               % MN                                                   ABS    __________________________________________________________________________    TOTAL SUM           REPS               18  140 44  44  38  45  95  23  12  3           LOCS               13  118 34  34  34  40  80  20  8   3           PH22G               102 101 101 104 94  88  102 112 99  100           PH19E               100 100 101 104 89  106 102 104 100 100           DIFF               3   1   0   0   5   18  0   8   1   0           PR > T               0.02                   0.24                       0.99                           0.99                               0.06                                   0.01                                       0.99                                           0.01                                               0.82                                                   0.99    __________________________________________________________________________               ECB DRP               2SC EAR               ABS % MN    __________________________________________________________________________    TOTAL SUM           REPS               1   52           LOCS               1   45           PH22G               2   100           PH19E               4   100           DIFF               2   0           PR > T  0.99    __________________________________________________________________________     *PR > T values are valid only for comparisons with Locs >= 10.

                                      TABLE 4A    __________________________________________________________________________    INBREDS IN HYBRID COMBINATION REPORT    VARIETY #1 = PHDN7/PH22G    VARIETY #2 = PHAA0/PHTD5    __________________________________________________________________________                   PRM BU   BU        TST SDG EST  GDU               PRM SHD ACR  ACR  MST  WT  VGR CNT  SHD               ABS ABS ABS  % MN % MN ABS % MN                                              % MN % MN    __________________________________________________________________________    TOTAL SUM           1   92  93  157.9                            107  97   53.1                                          102 99   100           2   90  90  152.8                            104  95   53.8                                          10o 102  98           LOCS               28  28  143  143  144  61  102 77   59           REPS               28  28  203  203  204  94  144 102  90           DIFF               2   2   5.1  3    2    0.7 2   4    2           PR > T               .000#                   .000#                       .001#                            .001#                                 .000#                                      .000#                                          .455                                              .001#                                                   .000#    __________________________________________________________________________               GDU STK  PLT  EAR  RT   STA STK BRT  GRN               SLK CNT  HT   HT   LDG  GRN LDG STK  APP               % MN                   % MN % MN % MN % MN % MN                                           % MN                                               % MN % MN    __________________________________________________________________________    TOTAL SUM           1   98  100  102  110  91   86  101 110  113           2   97  101  97   100  101  95  101 101  105           LOCS               28  180  63   63   50   51  124 25   3           REPS               43  275  97   97   75   75  180 35   3           DIFF               0   1    5    1o   9    8   1   10   8           PR > T               .999                   .000#                        .000#                             .000#                                  .000#                                       .112                                           .558                                               .007#                                                    .670    __________________________________________________________________________                DRP NLF  GOS HD   GIB EYE  ECB ECB  ECB                EAR BLT  WLT SMT  ERS SPT  DPE 1LF  2SC                % MN                    ABS  ABS ABS  ABS ABS  ABS ABS  ABS    __________________________________________________________________________    TOTAL SUM           1    100 5.0  5.8 100.0                                  6.5 6.6  97.4                                               3.6  5.1           2    100 4.2  7.5 93.1 5.3 6.3  95.4                                               3.6  4.6           LOCS 53  3    2   2    4   4    18  5    8           REPS 69  6    4   6    8   6    31  5    10           DIFF 0   0.8  1.8 6.9  1.3 0.4  2.0 0.0  0.4           PR > T                .999                    .199 .090*                             .388 .015+                                      .391 .047+                                               .999 .660    __________________________________________________________________________     * = 10% SIG     + = 5% SIG     # = 1% SIG

                                      TABLE 4B    __________________________________________________________________________    INBREDS IN HYBRID COMBINATION REPORT    VARIETY #1 = PHDN7/PH22G    VARIETY #2 = PHEM9/PHR25    __________________________________________________________________________                   PRM BU   BU       TST SDG EST  GDU               PRM SHD ACR  ACR  MST WT  VGR CNT  SHD               ABS ABS ABS  % MN % MN                                     ABS % MN                                             % MN % MN    __________________________________________________________________________    TOTAL SUM           1   91  93  151.0                            106  96  52.5                                         94  95   101           2   90  92  139.2                            98   95  53.2                                         97  103  99           LOCS               7   7   23   23   24  18  12  17   12           REPS               7   7   41   41   42  34  20  29   23           DIFF               2   1   11.8 8    2   0.6 3   8    1           PR > T               .126                   .100                       .004#                            .004#                                 .204                                     .028+                                         .705                                             .005#                                                  .023+    __________________________________________________________________________               GDU STK  PLT EAR  RT  STA  STK BRT  EYE               SLK CNT  HT  HT   LDG GRN  LDG STK  SPT               % MN                   % MN % MN                            % MN % MN                                     % MN % MN                                              % MN ABS    __________________________________________________________________________    TOTAL SUM           1   101 98   102 109  91  86   102 111  6.6           2   102 102  100.                            96   92  73   101 99   6.1           LOCS               5   27   9   9    9   8    25  4    4           REPS               10  48   18  18   14  12   43  6    6           DIFF               1   4    1   13   1   13   2   12   0.5           PR > T               .327                   .010+                        .262                            .002#                                 .396                                     .252 .523                                              .373 .252    __________________________________________________________________________     * = 10% SIG     + = 5% SIG     # = 1% SIG

                                      TABLE 4C    __________________________________________________________________________    INBREDS IN HYBRID COMBINATION REPORT    VARIETY #1 = PHDN7/PH22G    VARIETY #2 = PHM10/PHN37    __________________________________________________________________________                    PRM BU   BU        TST SDG  EST GDU               PRM  SHD ACR  ACR  MST  WT  VGR  CNT SHD               ABS  ABS ABS  % MN % MN ABS % MN % MN                                                    % MN    __________________________________________________________________________    TOTAL SUM           1   92   92  145.6                             105  97   53.3                                           106  99  99           2   92   94  128.7                             93   97   53.8                                           112  101 101           LOCS               21   19  76   76   78   45  54   58  28           REPS               21   19  113  113  115  71  76   75  45           DIFF               0    2   16.9 13   0    0.5 6    2   2           PR > T               .999 .000#                        .000#                             .000#                                  .999 .012+                                           .216 .181                                                    .000#    __________________________________________________________________________               GDU  STK  PLT  EAR  RT   STA STK  BRT  GRN               SLK  CNT  HT   HT   LDG  GRN LDG  STK  AFF               % MN % MN % MN % MN % MN % MN                                            % MN % MN % MN    __________________________________________________________________________    TOTAL SUM           1   98   99   102  110  90   82  102  111  113           2   102  101  106  100  104  91  98   98   100           LOCS               17   96   40   40   35   38  71   21   3           REPS               27   142  62   62   50   50  105  26   3           DIFF               4    1    4    9    14   10  3    13   13           PR > T               .000#                    .036+                         .000#                              .000#                                   .001#                                        .142                                            .001#                                                 .007#                                                      .423    __________________________________________________________________________                DRP NLF   GOS HD     GIB EYE    ECB ECB                EAR BLT   WLT SMT    ERS SPT    DPE 2SC                % MN                    ABS   ABS ABS    ABS ABS    ABS ABS    __________________________________________________________________________    TOTAL SUM           1    100 4.5   5.8 100.0  5.8 6.6    97.2                                                    5.2           2    100 3.0   6.5 100.0  5.0 7.0    96.1                                                    4.5           LOCS 41  1     2   1      2   4      8   3           REPS 51  2     4   2      4   6      13  5           DIFF 0   1.5   0.8 0.0    0.8 0.4    1.1 0.7           PR > T                .999      .500       .500                                         .547   .330                                                    .673    __________________________________________________________________________     * = 10% SIG     + = 5% SIG     # = 1% SIG

                  TABLE 5A    ______________________________________    SILAGE PAIRED COMPARISON REPORT    VARIETY #1 = PHDN7/PH22G    VARIETY #2 = PHAA0/PHTD5                    SI/                    WTA           TOTAL SUM                    ABS    ______________________________________           1        22.9           2        21.5           LOCS     3           REPS     5           DIFF     1.3           PROB     .145    ______________________________________     * = 10% SIG     + = 5% SIG     # = 1% SIG

                  TABLE 5B    ______________________________________    SILAGE PAIRED COMPARISON REPORT    VARIETY #1 = PHDN7/PH22G    VARIETY #2 = PHN37/PHM10                    SI/                    WTA           TOTAL SUM                    ABS    ______________________________________           1        22.9           2        22.6           LOCS     3           REPS     5           DIFF     1.6           PROB     .765    ______________________________________     * = 10% SIG     + = 5% SIG     # = 1% SIG

                  TABLE 6A    ______________________________________    HUSK COVER COMPARISON REPORT    VARIETY #1 = PHDN7/PH22G    VARIETY #2 = PHAA0/PHBF0                    HUSK                    COVER           TOTAL SUM                    % MN    ______________________________________           1        117           2        106           LOCS     23           REPS     37           DIFF     11           PROB     .044+    ______________________________________     * = 10% SIG     + = 5% SIG     # = 1% SIG

                  TABLE 6B    ______________________________________    HUSK COVER COMPARISON REPORT    VARIETY #1 = PHDN7/PH22G    VARIETY #2 = PHP02/PHTM9                    HUSK                    COVER           TOTAL SUM                    % MN    ______________________________________           1        114           2        103           LOCS     30           REPS     48           DIFF     12           PROB     .022+    ______________________________________     * = 10% SIG     + = 5% SIG     # = 1% SIG

                  TABLE 6C    ______________________________________    HUSK COVER COMPARISON REPORT    VARIETY #1 = PHDN7/PH22G    VARIETY #2 = PHAA0/PHTD5                    HUSK                    COVER           TOTAL SUM                    % MN    ______________________________________           1        114           2        96           LOCS     33           REPS     51           DIFF     18           PROB     .001#    ______________________________________     * = 10% SIG     + = 5% SIG     # = 1% SIG

                  TABLE 6D    ______________________________________    HUSK COVER COMPARISON REPORT    VARIETY #1 = PHDN7/PH22G    VARIETY #2 = PHRE1/PHTD5                    HUSK                    COVER           TOTAL SUM                    % MN    ______________________________________           1        116           2        97           LOCS     20           REPS     33           DIFF     19           PROB     .002#    ______________________________________     * = 10% SIG     + = 5% SIG     # = 1% SIG

DEPOSITS

Applicant has made a deposit of at least 2500 seeds of Inbred Maize LinePH22G with the American Type Culture Collection (ATCC), Manassas, Va.20110 USA, ATCC Deposit No. 209794. The seeds deposited with the ATCC onApr. 20, 1998 were taken from the deposit maintained by Pioneer Hi-BredInternational, Inc., 700 Capital Square, 400 Locust Street, Des Moines,Iowa 50309-2340 since prior to the filing date of this application. Thisdeposit of the Inbred Maize Line PH22G will be maintained in the ATCCdepository, which is a public depository, for a period of 30 years, or 5years after the most recent request, or for the effective life of thepatent, whichever is longer, and will be replaced if it becomesnonviable during that period. Additionally, Applicant has satisfied allthe requirements of 37 C. F. R. §§1.801-1.809, including providing anindication of the viability of the sample. Applicant imposes norestrictions on the availability of the deposited material from theATCC; however, Applicant has no authority to waive any restrictionsimposed by law on the transfer of biological material or itstransportation in commerce. Applicant does not waive any infringement ofits rights granted under this patent or under the Plant VarietyProtection Act (7 USC 2321 et seq.). U.S. Plant Variety Protection ofPH22G has been applied for under Application No. 9700222.

The foregoing invention has been described in detail by way ofillustration and example for purposes of clarity and understanding.However, it will be obvious that certain changes and modifications suchas single gene modifications and mutations, somoclonal variants, variantindividuals selected from large populations of the plants of the instantinbred and the like may be practiced within the scope of the invention,as limited only by the scope of the appended claims.

What is claimed is:
 1. Seed of maize inbred line designated PH22G,representative samples having been deposited under ATCC AccessionNo.209794.
 2. A maize plant, or parts thereof, having all thephysiological and morphological characteristics of inbred line PH22G,representative seed of said line having been deposited under ATCCaccession No.
 209794. 3. The maize plant of claim 2, wherein said plantis male sterile.
 4. A tissue culture of regenerable cells of a maizeplant of inbred line PH22G, wherein the tissue regenerates plantscapable of expressing all the morphological and physiologicalcharacteristics of the inbred line PH22G, representative seed of whichhave been deposited under ATCC Accession No.209794.
 5. A tissue cultureaccording to claim 4, the cells or protoplasts being from a tissueselected from the group consisting of leaves, pollen, embryos, roots,root tips, anthers, silks, flowers, kernels, ears, cobs, husks, andstalks.
 6. A maize plant regenerated from the tissue culture of claim 4,said plant, capable of expressing all the morphological andphysiological characteristics of inbred line PH22G, representative seedof which have been deposited under ATCC Accession No.209794.
 7. A methodfor producing a first generation (F₁) hybrid maize seed comprisingcrossing the plant of claim 2 with a different inbred parent maize plantand harvesting the resultant first generation (F₁) hybrid maize seed. 8.The method of claim 7 wherein inbred maize plant of claim 2 is thefemale or male parent.
 9. An F₁ hybrid seed produced by crossing theinbred maize plant according to claim 2 with another, different maizeplant.
 10. An F₁ hybrid plant, or parts thereof, grown from the seed ofclaim
 9. 11. A process for producing inbred PH22G representative seed ofwhich have been deposited under ATCC Accession No. 209794,comprising:planting a collection of seed comprising seed of a hybrid,one of whose parents is Inbred PH22G said collection also comprisingseed of said inbred; growing plants from said collection of seed;identifying said inbred plants; selecting said inbred plant; andcontrolling pollination in a manner which preserves the homozygosity ofsaid inbred plant.
 12. The process of claim 11 wherein said step ofidentifying said inbred plant comprises:identifying plants withdecreased vigor.
 13. The process of claim 11 wherein said step ofidentifying said inbred plant comprises:identifying seeds or plants withhomozygous genotype.